A 4kb deletion in genomic DNA results in the absence of 241bp in the mRNA and the addition of 67bp of novel sequence, a 174bp net loss. The region that is deleted corresponds to 5 amino acids N-terminal to the transmembrane domain of the encoded protein, and results in termination of the open reading frame after an additional 3 amino acids. The resulting protein is a soluble truncated one, lacking both transmembrane and cytoplasmic domains. Northern analysis indicates that mRNA is transcribed at nearly wild-type levels in adult tissues.